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Vaporstat question

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BMurrins
BMurrins Member Posts: 45
in Strictly Steam
Hello all.

Thanks to the help of you knowledgeable pros here, I was able to successfully revive my mistreated 2 pipe vapor system for a large 25 unit building.

It was laborious and a little expensive but well worth it. Our average boiler run time per cycle is down ~70% from last year, and the building is now evenly heated. A million thanks to you guys.

When the boiler runs and has established steam, it doesn’t surpass 4oz of pressure. My question: should I adjust the vaporstat to cut out at 4oz or should I leave it at 8 oz and not bother changing anything?
CLamb

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  • ethicalpaul
    ethicalpaul Member Posts: 5,708
    edited January 16
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    I don't own a building, but since you know it can heat successfully at 4oz I'd be tempted to move it there.

    But first I might leave it at 8 for awhile to see if it ever goes up there, like on a real cold day, just for my knowledge of the system. But IMO there's no reason to build any pressure
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    BMurrins
  • delcrossv
    delcrossv Member Posts: 742
    edited January 16
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    Unless it's to recover from a setback, ours doesn't cycle on pressure either. I'd leave it up and see how the system performs. An 8 oz cutout is pretty modest for a 25 flat.
    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    BMurrins
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,574
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    It's not going to make much difference. If the pressure does not rise above 8oz your fine. Is the burner a fixed fire burner or does the flame have low-high fire or full modulation?

    You say the boiler cycles are down 70%. What shuts the boiler down? Pressure, thermostat or a heat timer control?
  • BMurrins
    BMurrins Member Posts: 45
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    EBEBRATT-Ed said:
    It's not going to make much difference. If the pressure does not rise above 8oz your fine. Is the burner a fixed fire burner or does the flame have low-high fire or full modulation? You say the boiler cycles are down 70%. What shuts the boiler down? Pressure, thermostat or a heat timer control?
    Fixed fire burner.

    Heat timer shuts it down. 

    I’ve sat down and watched it cycle since fixing the system and even on our coldest days of this winter, it hasn’t come close to shutting down on pressure.

    On the coldest morning we’ve had so far (10-15ish degrees) I went over to take a look and near the end of its cycle it was holding steady at slightly under 5 oz.
    ethicalpaul
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,574
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    If it's heating the building that is as close to perfect as you will get.
    BMurrins
  • mattmia2
    mattmia2 Member Posts: 9,707
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    the heattimer is sort of doing the same thing as the vaporstat, no reason to turn the vaporstat down and make them compete.

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